#include<stdio.h>
#include<math.h>
int main()
{
	double a,b,c,s,p,area;
	scanf("%lf %lf %lf",&a,&b,&c);
	p=a+b+c;
	s=(a+b+c)/2;
	area=pow(s*(s-a)*(s-b)*(s-c),0.5);
	if(a+b>c&&a+c>b&&b+c>a)
		printf("area = %.2f;perimeter = %.2f",area,p);
	else
		printf("These sides do not correspond to a valid triangle");
	return 0;
}
